Optical device and display device

Abstract

An optical device includes a laser light source; a first optical integrator configured to transmit laser light emitted from the laser light source; a second optical integrator configured to transmit the laser light emitted from the first optical integrator; and a retardation plate disposed between the laser light source and the second optical integrator, and configured to transmit a portion of the laser light so as to rotate a polarization of the transmitted portion of the laser light by 90 degrees.

What is claimed is: 
     
         1 . An optical device comprising:
 a laser light source;   a first optical integrator configured to transmit laser light emitted from the laser light source;   a second optical integrator configured to transmit the laser light transmitted through the first optical integrator; and   a retardation plate disposed between the laser light source and the second optical integrator, and configured to transmit a portion of the laser light so as to rotate a polarization of the transmitted portion of the laser light by 90 degrees.   
     
     
         2 . The optical device according to  claim 1 , wherein the retardation plate transmits one-half of the laser light. 
     
     
         3 . The optical device according to  claim 1 , wherein
 the laser light source is a light emitting device including a plurality of semiconductor laser elements, and   the laser light emitted from the light source comprises laser light beam emitted from each of the plurality of semiconductor laser elements.   
     
     
         4 . The optical device according to  claim 1 , wherein
 the laser light beam emitted from each of the plurality of semiconductor laser elements is separately incident on the retardation plate, and   the retardation plate transmits one-half of the laser light beam emitted from each of the plurality of semiconductor laser elements.   
     
     
         5 . The optical device according to  claim 1 , wherein
 the laser light source is a light emitting device including a plurality of semiconductor laser elements, and   the laser light emitted from the light source comprises laser light beam emitted from the at least one semiconductor laser element of the plurality of semiconductor laser elements.   
     
     
         6 . The optical device according to  claim 5 , wherein the retardation plate is disposed so as to transmit one-half of the laser light emitted from the at least one semiconductor laser element of the plurality of semiconductor laser elements. 
     
     
         7 . The optical device according to  claim 1 , wherein the laser light source emits a plurality of laser light beams having different colors. 
     
     
         8 . The optical device according to  claim 7 , wherein
 the laser light beams of different colors are separately incident on the retardation plate, and   the retardation plate transmits one-half of each of the laser light beams of the different colors.   
     
     
         9 . The optical device according to  claim 1 , wherein
 the retardation plate is disposed in a first region on a plane perpendicular to an optical axis of the optical device and no retardation plate is disposed in a second region on the plane, the first and second regions being adjacent to each other with a line passing the optical axis therebetween.   
     
     
         10 . The optical device according to  claim 1 , wherein the retardation plate is disposed between the laser light source and the first optical integrator. 
     
     
         11 . The optical device according to  claim 10 , wherein each of the first and second optical integrators includes one or more fry-eye lenses and one or more lenses following the one or more fry-eye lenses in a light transmitting direction. 
     
     
         12 . The optical device according to  claim 1 , wherein the retardation plate is disposed between the first optical integrator and the second optical integrator. 
     
     
         13 . The optical device according to  claim 12 , wherein each of the first and second optical integrators includes one or more fry-eye lenses and one or more lenses following the one or more fry-eye lenses in a light transmitting direction. 
     
     
         14 . The optical device according to  claim 1 , further comprising:
 an optical combiner disposed between the laser light source and the first optical integrator, and configured to combine a plurality of laser light beams so as to form combined light, wherein   the retardation plate transmits a portion of the combined light of the plurality of laser light beams so as to rotate a polarization of the transmitted portion of the combined light by 90 degrees.   
     
     
         15 . The optical device according to  claim 14 , wherein
 the plurality of laser light beams emitted from the laser light source have different colors, and   the optical combiner includes a mirror group configured to combine the plurality of laser light beams having the different colors.   
     
     
         16 . The optical device according to  claim 14 , wherein the optical combiner includes a beam expander configured to increase a maximum width of the combined light in a direction orthogonal to an optical axis of the optical device. 
     
     
         17 . The optical device according to  claim 14 , wherein
 the retardation plate is disposed between the optical combiner and the first optical integrator, and   the combined light through the optical combiner is perpendicularly incident on an incident surface of the retardation plate.   
     
     
         18 . The optical device according to  claim 14 , wherein the retardation plate is disposed on a side of the first optical integrator opposite to a side on which the optical combiner is disposed. 
     
     
         19 . A display device comprising:
 the optical device of  claim 1 ;   a spatial modulator configured to generate an image by modulating spatial intensity distribution of the laser light from the optical device; and   a lens configured to project the image generated by the spatial modulator.